org.archive.wayback.util.partition
Class Partitioner<T>

java.lang.Object
  org.archive.wayback.util.partition.Partitioner<T>

Type Parameters:

T - generic class type to use with this Partitioner

public class Partitioner<T>
extends Object

Class which divides a set of date-related objects into sub-sets by time ranges. This class provides methods for: 1) determining the smallest PartitionSize that can be used to cover a time range, using at most a set number of partitions 2) creating a List of Partition objects covering a span of time, each having a specified size 3) efficiently populating an iterator of date-related objects into List of Partition objects

Author:

brad

Field Summary

static PartitionSize	daySize PartitionSize based on Day intervals
static PartitionSize	hourSize PartitionSize based on Hour intervals
static PartitionSize	monthSize PartitionSize based on Month intervals
static PartitionSize	twoMonthSize PartitionSize based on Two Month intervals
static PartitionSize	twoYearSize PartitionSize based on Two Year intervals
static PartitionSize	weekSize PartitionSize based on Week intervals
static PartitionSize	yearSize PartitionSize based on Year intervals

Constructor Summary

Partitioner(ElementPartitionMap<T> map)

Method Summary

void	dumpPartitions(List<Partition<T>> partitions) Debugging method
List<Partition<T>>	getRange(PartitionSize size, Date start, Date end) Create a List of Partition objects of the specified size, which span the date range specified.
PartitionSize	getSize(Date first, Date last, int maxP) Attempt to find the smallest PartitionSize implementation which, spanning the range first and last specified, produces at most maxP partitions.
static PartitionSize	getSize(String name) Get a PartitionSize object by it's name
void	populate(List<Partition<T>> partitions, Iterator<T> itr) Add elements from itr into the appropriate partitions.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

hourSize

public static PartitionSize hourSize

PartitionSize based on Hour intervals

daySize

public static PartitionSize daySize

PartitionSize based on Day intervals

weekSize

public static PartitionSize weekSize

PartitionSize based on Week intervals

monthSize

public static PartitionSize monthSize

PartitionSize based on Month intervals

twoMonthSize

public static PartitionSize twoMonthSize

PartitionSize based on Two Month intervals

yearSize

public static PartitionSize yearSize

PartitionSize based on Year intervals

twoYearSize

public static PartitionSize twoYearSize

PartitionSize based on Two Year intervals

Constructor Detail

Partitioner

public Partitioner(ElementPartitionMap<T> map)

Parameters:

map - that converts from the Generic type used in this instance to a Date, and adds a Generic type used to a Partition

Method Detail

getSize

public static PartitionSize getSize(String name)

Get a PartitionSize object by it's name

Parameters:

name - of the PartitionSize

Returns:

PartitionSize matching the name, or a TwoYearPartionSize if name is unknown

getSize

public PartitionSize getSize(Date first,
                             Date last,
                             int maxP)

Attempt to find the smallest PartitionSize implementation which, spanning the range first and last specified, produces at most maxP partitions.

Parameters:

first - Date of beginning of time range

last - Date of end of time range

maxP - maximum number of Partitions to use

Returns:

a PartitionSize object which will divide the range into at most maxP Partitions

getRange

public List<Partition<T>> getRange(PartitionSize size,
                                   Date start,
                                   Date end)

Create a List of Partition objects of the specified size, which span the date range specified.

Parameters:

size - of Partitions to create

start - Date of beginning of time range to cover

end - Date of end of time range to cover

Returns:

List of Partitions spanning start and end, sized size, in date- ascending order.

populate

public void populate(List<Partition<T>> partitions,
                     Iterator<T> itr)

Add elements from itr into the appropriate partitions. Assumes that all elements fit in one of the argument Partitions, that the partitions are in ascending order by time, and that elements returned from the Iterator are in ascending time order.

Parameters:

partitions - to populate with objects

itr - ascending Iterator of objects to place into the partitions

dumpPartitions

public void dumpPartitions(List<Partition<T>> partitions)

Debugging method

Parameters:

partitions - to dump